This month, one Brooklyn bar is putting a feminist spin on the idea of ladies' night.

On Tuesday, July 7 (or 7/7), DNAinforeports that Prospect Heights' Doctor Who-themed bar the Way Station will protest against income inequality between the sexes by charging all female patrons just 77% of their total bar tab.

In an email message provided to DNAinfo, the bar's owners wrote that the gender pay gap is "some shameful shit" and urged patrons to help them "level the playing field, even if it is just for one night. Women deserve better. Recognizing this discrepancy is just a start."

Where the 77% number comes from: It's the Labor Department figure most often used by the White House and feminist organizations advocating for equal pay for equal work.

As the Washington Post's Glenn Kessler explains, the statistic captures the aggregate compensation of all full-time women as compared to all full-time men. In doing so, critics argue that the 77% statistic tends to overstate the difference between male and female workers at the same seniority levels in the same professions, since men disproportionately occupy higher-paying positions in most industries and have a solid lock on Science, Technology, Engineering and Mathematics jobs.

While Politifact reported that the actual pay gap that could be attributed solely to discrimination was likely in the range of 93% to 95% of every dollar made by men, it also noted that the pay gap persists because women are systematically excluded from the same kinds of economic opportunities that their male colleagues find much easier to obtain.

It's real and it hurts: Gallup polling, for example, has found that 15% of women believe they were denied a promotion at work on the basis of their gender. ThinkProgress' Bryce Covert notes that women make less than men at every seniority level, regardless of education or skill required or the industry they work in.

As the Labor Department argues, this impact is noticeable from the lowest echelons of industry to the CEO level.

So while getting 23% off a bar tab one night in Brooklyn won't fix these gaps, it is a fun and innovative way to draw attention to an issue that affects almost every woman in the country.